Test for H. pylori, eat the medicine should be referred to do carbon 13 or carbon 14 blow test, the carbon 13 or carbon 14 capsule taken orally, the capsule inside is mainly contains carbon 13 or carbon 14 urea capsule. Swallow this capsule in the body during fasting, if the subject has H. pylori in the stomach, the urea capsule by carbon 13 or carbon 14, the urease produced can quickly break down the urea into carbon dioxide and ammonia, and the carbon dioxide goes through the blood into the lungs and out of the body. Therefore, the expired carbon dioxide 13 and carbon dioxide 14 gas can be collected during exhalation and then tested on the instrument to determine whether the subject has been infected with H. pylori.